ee o ne,

e e

THE "BUZZ"

What is that annoying Buzz in the 2068? It always seems to happen when typing in a lengthy BASIC program, doesn't it? Well, there are good reasons for it because your machine is trying to tell you that you goofed somewhere. If you have never heard the Buzz then try the following:

(for THE TS2068 ROM) (for the SPECTRUM ROM)

CLEAR 26790 - CLEAR 23850 -

Now type anything and there it is... that annoying Buzz. The computer is telling you that the Basic Memory is too full. You lowered RAMTOP so that there are only a few bytes for Basic and it cannot accept them. If there was a little more room in memory you may have seen the error messages:

u MEMORY FULL" or " NO ROOM FOR LINE"

|, TORONTO TIMEX

P. O, Box 7274 Stn. A Toronto, Ont., MSW IX9

SINC - LINK

Jan.- Feb. 1986

NEWSLETTER INDEX

PRESIDENT'S MESSAGE LARKEN DD LOADER SINCBITS ` ZX81 NEWS SPECTRUM TAPE BACK-UP QL CORNER BOB'S NOTEBOOK LUNAR CALCULATING TS2068 PLOT § SCROLL P.10 HINTS-N-TIPS P.il

DISK DROPPINGS Peiz

Another situation where Buzz occurs is when you type in a line longer than the 23 screen lines. You may or may not want to try this one. However, any more typing than 23 lines is not ignored even though it goes off the screen and you can't see it. The Buzz will sound for each key hit just to annoy you and hint that you have typed a long, long line. Getting back to typing in a lengthy Basic program; you eventually get tired and accidentally confuse your shifts on the top row of keys.

This causes a control character to be entered into a line where it shouldn't be (often changes colour of listing). By re-LISTing the program the length of that line may get corrupted and makes your 2068 think it's too long. This is where it tells you to Buzz off. Only extensive PEEKing and POKEing can repair the damage in the program,

from: SPECTRUM Users Manual, Chapter 24 compiled by Fred Schakel London T/S Users Group

SINCLAIR USERS CLUB

Canada

LARKEN DISK DRIVE OPERATION by George Chambers

One irritating thing about the LARKEN drive is the need for some 26 keystrokes to get the drive operational, This article provides an effective solution to the problem. What I have done is modify an ordinary tape cassette to do the task for me,

The modification consists of removing the existing reels in the cassette body and replacing them with a 12 inch continuous loop of tape. This length of tape is sufficient to hold a short "boot" program which gets the drive up, and to load a program called “menu.81",

What we are going to do is to remove the reels and tape from the cassette, and mount two additional rollers in the cassette body to guide tne tape loop. inen make up an endless loop of tape, install it, and close up the cassette.

Now to get down to details. First pick a cassette which is fastened with screws, This will make it easy to take apart. Actually you will need a second cassette because we need a second pair of the little rollers and their bearing pins, to mount inside the first cassette, i

Open both cassettes. Discard the reels, lubricating paper inserts, and tape. (Save a few feet of tape to make up the tape loop). Carefully remove and save the two rollers and pins from one of the cassettes, The two additional rollers are be mounted inside the other cassette near the two knockout tab recess. The idea is to provide as lang a tape path as possible.

You will need a small drill just about the diameter of the roller pins. Assemble the cassette case and dril] two small holes completely through the cassette, just where the new rollers are to be installed. These holes should provide a press fit for the roller bearing pins, Make sure the holes are perfectly at right angles to the cassette body, so that the rollers roll freely, and do not bind.

Open the case and install the pins, and rollers. See that they turn readily.

Now measure a length of recording tape. It should be just the length of the path around the four rollers in the cassette, Splice the tape. You may have to make several tries, If the tape loop is too short it obviously will not go over the rollers; if it does it may still be too tight and bind. On the other hand it may be too long. If it is too long this will be apparent by a bulge of tape appearing near the pressure roller in the tape deck when it is in operation, instead of being drawn promptly into the cassette.

Page L

One® you have your cassette made up it will be necessary to save a program onto it. A suitable program is shown elsewhere in this article, The program boots the drive and calls up a program. 1 make use of a small Basic program on each disk which is either a MENU program, or a simple loader for a main program such as TASWORD.

Type the program in, then start recording on this tape. Simply SAVE the program by entering SAVE “boot” LINE 10. Watch the SAVE process, and stop the recorder IMMEDIATELY the SAVE ends, Test by reloading, or better still MERGE it. (This way you will not lose the program you have typed in.) Chances are that you have SAVfd it over the splice, in which case you will get a load error, Record it again, and again if necessary, until you have a good save. Remember it is erítical to stop the recorder immediately after the save, No dallying here,

boot program: 10 CLEAR 61000: OUT 84,64: PRINT USR 63488 20 REM load "menu.Bl"

PRESIDENT'S MESSAGE

There has been a development in our club newsletter which has been very gratifying to tha newsletter editor and myself, and which is worthy of mention this issue,

This has been the appearance of regular contributors to our newsletter. First there was lan Robertson with his “"SINCBITS", Then Peter McHullin with his "ZX81 NEWS AND RESOURCES", and John Burns and Dave Ridge with a continuing column "TELECOMPUTING",

May I extend a warm thank you on behalf of our membership to last years columnists, who made our newsletter such an outstanding success. We look forward to the continuance of their columns in the coming year.

This year we are delighted to welcome three more columnists to our newsletter. We are to have Peter Hacksel, who will be covering the Disk Drive scene, specifically the LARKEN Drive. Also Enore Gardinio with a regular column devoted to the new OL: and not least, Karim Rahamet with a Hacker's column,

At the same time, we must applaud the.work80f our editor, John Roach, without whose efforts this whole newsletter production would not have been possible, Thanks, John,

Yours in computing, George Chambers,

SINCAITS

lan Robertson Compuserve 72147,3401 FIDO HET 148/HODE 608

UPDATES: Those of you who correspoad via FIDONET - PLEASE NOTE MY NEY NET 148 NUMBER. It’s nice to see gore and more people stating ia print that the Timex/Sinclair market has not died, but instead has developed into a sarketplace with fener products, but of a much higher quality, There is another 2068/Spectruw compatible DDI on the market, it is the John Oliger Disk Drive Inerface. It is available is four configurations, from JOHN OLIGER COMPANY, 11601 WHIDBEY DRIVE, CUMBERLAND, IN 46229; al the two bare boards $44,00 b} asa kit with all parts $99.00, c) assembled and tested (without NHI) $120.00, and lastly, d) assembled and tested (with MAI) for $130.00. MMI stands for "non saskable jnterupt", which simply aeans that ras contents can be dumped to disk at the touch of a button. All prices are in US funds and include the JLO SAFE NOS on $k eprom plus postage. In order to operate this DDI you wust also buy the Oliger expansion board. I now have my bare boards assenbled and an in the process of testing. On power-up the JLO SAFE DOS checks to see which ROM is being used - f can report that this aspect really works. One last ward "this DOS 15 FAST", sore in the next issue. I recoivad a replacenent microdrive back from Sinclair Research, in about four weeks time, and at no cost! Not too shabby I must say! The only problem is - this one is also noisy and slightly out of alignment!! At least it is better than the one I returned, Now that the cost of 254k chips is coming down, one smart UK company will install them inside the aL, to enable the owner to run 512K. The only side effect is that the system apparantly does not run as fast as a similar 8l with outboard RAM. QL owners take note!! My wife would like sozobody to keep reminding we that the present version of the al will probably be replated by either @L II or a completely different business type machine and further that 1 already have too nany obsolete computers.

192068: There is definately a mouse in wy house! it is a Radio Shack CoCo? anuse connected to the Zebra Graphics Pad Interface (with a slight modification). AND IT WORKS! To be able to use

Tech Draw without all that "screen spatter" is quite a treat. Now that Anchor has dumped their 752050 andea line, there are a lot of bargains around. Zebra Systems Inc., 78-06 Jamaica Ave., Woodhaven NY 11421, telephone (718) 276-2383 are selling the complete modem for $72.95 US (including shipping). Various others are selling the board/cables for $25.00, Zebra are also selling an uatested/uncased board for $13.00 each, $28.00 for three and $73.00 for a quantity of ten. The message is - IF YOU WANT A 2050 NODEN GET IT NOW. The latest version of MSCRIPT is available from Zebra. Looks good. An even wore up-to-date version is available from Jack Dohany, 325 O'Connor Street, Menlo Park, CA 94025. He sells upgrades ONLY to bona fide MSCRIPT owners - pirates stay away. He operates his own company called "Fairuare” and needless to Say the prices are “fair”.

SPECTRUM: Wy big news item tor the Spectrum is that I nou have the Technology Research "Bota" DDI up and runniag on my “plus” complete with 1F1 and two wicrodrives. WHAT A SYSTEM!!! 1t

SINC-LINK JAN/FEB 1996

comes with 25.25" utility disc, which I can use on the quad

drive or can be trasterred to a 3" disk. Very flexible! It is possible to switch frow DOS to Sinclair Basic by sottware commands. This weans that disks, aiceodrives and cassette can be ases at any tine without a problem. Using the “magic button” on the DDI f can duap the RAM contents to disk at any time. This weans that ALL games can be put on disk and can come up ruming at the location on screen when the button was pressed. So far I have about 40 games on disk - and they take a "slow" nine to ten seconds to load. Even for a non-games person like ayselt this makes playing games easier {and tempting). The disks tormat to 160k and this allows 3 games to be saved to each side of the disk. The Abbeydale SPDOS formats to 184k on each side of the disk las in the Ramex DDI and probably the KEMPSTON). The AMX souse package is now 970.00 (pounds sterling, down from the original 189.00. Hope it goes even lower. There has been considerable press regarding "lenslok*, a software protection device which looks like a small folding wagnitying glass. The observations have been aixed - the software people like it and it appears that the users are not quite so sure. Think about it, how would you like to look at a ‘very bright" screen through a pagnifying lens to load a stubborn program. Apparently FIREBIRD used it on their latest program "Elite* and are quoted as saying that they are considering not using it in the future, due to very bad reviews about their instructions for using lenslok. If you are into computer games, then you MUST try "Tomahawk" by Digital Integration. It seems to be the best flight simulator available, even if it is a helicopter ibut what a helicopter!)

DISK DRIVES! I wil) comment only cn the financial aspect of using DD with either the Spectrum or the 2068. The following approximate prices are in our lowly Cdq. dollar, with custoas duty and delivery included. The prices will also include 2 drives, power supply and cases except where noted as DDI {disk drive intertace) only. RAMEX/ANDEK ITI system 5520.00 trom RANEX INTERNATIONAL, 17420-26 WILE ROAD, WASHINGTON, NI 48074 telephone 313-781-5800, ZEBRA/TIMEX $810.00, AERCO $825.00 FROM ACNE ELECTRIC ROBOT CO, BOX 18093, AUSTIN, TEXAS 78760 telephone 512-451-5874. JOHN OLIGER (DDI) $270.00 (includes JLG extender board at $84.00 Cdn), this price cas be reduced if you do-it-yourself {see UPDATES above). LARKEN (DDI) $135.00 from LARKEN ELECTRONICS , RR #2, NAVAN, ONTARIO K4B 1H7. TECHNOLOGY RESEARCH "BETA" from Bob Dyl uf ENGLISH MICRO CONNECTION, {5 KILBURN COURT, NEWPORT RI 02840, telephone 401-849-3805, Spectrum only DDI $290.00. Bob also sells the Kempston (5PDOS) DDI - if anybody has one I would appreciate a comment or two. As you can see the world of mass/fast storage is an expensive one. Reneaber one thing - unless you want to use a DD system exclusively for either games or business applications "almost any system will do’, therefore, betore you buy "ask somebody who has one”.

TSIQQO/ZX81; Anyone interested ia joining a COMPUSA USER'S GROUP should write to the following address; CUSS, P.O. Box 2186 Inglemood, SA 70309. It is being formed by Tony Gomez and Ed Srey. If you want into faster Tony can be reached at FIDO Met 102 Node 602 and Ed can be reached at FIDO Net 102 Node 106 and

on CompuServe 75234, 3233. By the way, CUSS stands for "Compusa Users Support Group". I have a copy of their user questionaire, if anyone is interested,

PAGE 3

2B NEWS *G BY PETER MOMULLIMN

SINC-LINK VYOL-4 NO- 1

k RESOURCES JAN/FEB 360

listings neyt issue, but a late mention! RE HOBRYIST HONDEDER TO tx Bruce Taylor, of Budget Robotics 4& ; son, au731, has announced the y BUILD à MICROCOMPUTER- CONTROLLED ROBOT

a a ar Au

a $ En Bu

x=

E H B Books had oneg the rights for a u

AND OTHER COMPUTER CONTROL proyecte. {quite a mouthful!)

TA aver 3 year, then decided not to publish, After this runaround, Mr. Taylor's company bought back the rights and is now publishing the book, This book presents the design of an award-winning robot in thoroughly documented project fora, and promises to be a valuable reference on interfacing just about anything. Printed circuit boards will be available from Budget Robotics for avery project 7 the book. Chapter topics include Adjustable Power Supply, S299 PIO Board, Digitalker voice synthy, Stepper Motor Drivers, Optical Encoders, Polaroid Ultrasonic Ranging kit, and others, 200+ BILL" pages, o0+ illustrations, bt tables, loosebound. Price; 4,3.$13,06, ppd.

For a sample of previously published work, see “Robotics on a Budget”, p.18, SYNC Vol.3 No.4j also Hone. ne an a Budget”, pdl, SYNC Vol,4 No.1; both by Bruce €. Taylor, Budget Robotics holds rights to an improved version of the er Cont ñ as well as u

4 invua buttered bus expansion board, the 2 i, an inexpensive general purpose parallel 1/0 hoard. krite for details- Bruca replies promptty.

BE HOLT MODEM, BRATHAN! stridge 2050 modeas, tested, with phone cables but no (OF power supply are available tram DAVE CLIFFORD, 13910 LE AVE., GARDENA, CA 70249, (210)-014-0648. The price? a for ong, three or gore for $22.50 each, ten or aore 20,0 bt q

ma

AA

s 1.5, bucks, including delivery. At tine at icated he had about 1300 left. However, he á closed number of untested boards which are ga ailea of ainor parts (an LED & resistor). Plans are ell these as-is at an even cheaper price, including a

aplete schematic è parts ID for tha hardware hacker. ei to say, I ordered my modem the same day I heard about Mr. Cli ttord, as well as a capy of RIRI-180D 1,7, at

cz En alt ro pu > <= tes

which is 1900 (or the WOr

said to be the best 20481), Dave [l

a version of # i version, then a «4 col. ld be an interesting challenge te werk up a 64 for the JLU Video TS1000! For a short but sweet 1 i

t

da o Me I a mec En

[va]

DAA, first a 32-coluan

moos reo soa ey bet E

on

cor

see Telecom Treats, in Sinc-Link , q de Richardson.

The warped checkerboard" graphic on the bottom of

ue, 435 Cr A dona 751000 using a graphics

1

ara bol

iste ae conn ee to Since Artist for printed gut s size-as on this Epson MX30,

Fer HARDWARE USER REPORT age SUBJECT: The SERCO FO-24 Floppy Disk System. SOURCE; SERCO, 7506 ROBALE RD., AUSTIN, TX 7873

FE-2¥ Flappy Disk Controller Board 4 D05: 15.4179, 60 futo Boot REM Board: Ud. $ 39,00 auto Boot ROM Board with Cantronits I/F! Lat 99,

Complete packaged systens are alse available. SEE "Pug Alert’, page 4 last issue, fora discussion of the Boot ROM / Centronics Board. BASIC TECHNICAL SPECIFICATIONS: Driva type! Shugart compatible 3,3" or B” drives, Lor í side, single or double density, 33 ar 4) tracks/sida, up ta 4 400K bytes TSM readable, 10 sectors per track, S12 bytes/sector.

4 of Drives: 29/00 Capacity: Disk Fermat:

# Files per Disk up to 20 (as 4etrack * a ") up ta 5 fas {Sebrack agas!) Memory Use! 2K DOS in EPROM, and Fae at 12-14

FDU 1/0 is memory mapped. approx. 33 sec, poros. 1 ain. 5 sec sec, (20k page) % ser. (40K gage) Es! WRITE PROTECTED; INSUFF. RAN; DISK ERROR 5 Cirguit board is anoros. 4.5"44", plus gold finger sx Io 1797 FRC (Siemens); 9214 Data Separator

Format DSPD; Copy DSDD-DSDD; Avg. LOAD/SAVE:

wed Shu

Special Ile:

WRAT BO YOU SEE when you open the box containing your

newly- arrived SERCO FD-2X7 One untesed controller Soard, a computer bus ribbon cable, one floppy disk, and a 16 pag

manual, What else de you need? Disk drive(s), drive a cases, & power supply. Aarco’s manual gives reasonably Sasy- to- follow instructions for hooking up your system, and has several useful illustrations. The power supply must provides +V at 2-3 aaps, and +5V¥ at 3 amps. The drive cable required

is a standard IBM/Shugart 34 conductor pc-edge type. If you

follaw ferco's instructions to the letter, you will likely void any warranty on your new drives, The FDE Board gets its +34 and +12V supplies via pins 2 and 34 on the disk drive edge connector, Pin 34 is normally unused, but pin 2 is connected on some drives, Aerco recommends you cut any traces see to pins 2 or 34 on the drive, and jumper these conductors over to the power supply pins. This way, you connect the power supply only to ane drive, and the FRC Board & other drives get powered thru the ribbon cable, The result is tidy, but I fate having to hack up a new drive! The alternativa wouid te to cut wires 2 & 34 adjacent to the controller card, and run separate power leads to PA a. Í did it Rerco's way.

Having hooked up drives & power supply, the fD-2t plugs into the o ribbon cables then the RAM pack, ati the ribbon cable's male edge extender, and we're ready what’s on ĝerco's "master" disk.

PAGE 4.

K cursor appears. Following sk is placed in Drive a. ises the 305, and loads ia

awing asenu appears on the

i ne pi ne disk. The f ut

7 4 n

2 5 WELCOME TO SADOS+ 14K 9/83

ca “a

fe) 3 ed ea oes

IN DIRECTORY

“A =

DISK IN DRIVE A HO HEX MONITOR ~ LOAD MEMORY FROM DISK 3 e S SAVE MEMORY ON DISK Nothing too surprising here. Some further exploration of the manual reveals several interesting facts. All DOS functions are accessed via RAND USR commands. The "DOS" program supplied on page i oof the master disk serves tuo purposes: 1) If is a “user-friendly interface’ (oh cliche, cliche!) to the 005 USA routines, and 2) It contains the Disk Directory.

ent DOS control programs are supplied, a "Lak" i a "EAK" version, (All capacities specified here

are for a a0 track, ad drives } h

E H Two d aire

k s diski is ida into 20 4 track pages. bny pies 1 page, regardless of whether it is 4 ae lėk program. Each "16K" disk page will

mu m re E Eu o eet

ero rr or a nu an

a the full potential storage capacity of gas 5 pages per disk, each page yt

si L u

5 n a havia ty af ¿0£ bytes. It is otherwise identical to rogr ag.

The ŝerco DOS does nol record a filename with each program, nor dues it automatically maintain a directory. Programs are loaded & saved oy > number. It is the user's responsibility to keep the directory on page i updated.

Converting a Grea oe program te a disk version is quite

uses SN USR calls for SAVE & LOAD

commands: RAND USR il } ta SAVE to a specified page, or RAND USR (12290+PAGE) to pe from a specitied page. After loading a program froe tapa, the DOS sust be initialised by the con@and RAND USR 12063. “te consan bel initialises the FOC nd loads certain DOS parameters into bytes 14307/16508. Thus, the lines: 9900 SAVE "PROGRAR" 9910 ELS 9920 RUR „KOULO be replaced by the lines: 9960 RAND USA 12053 9903 RAND USE 12722 9910 CLS 9920 RUN In this example, a 0070 7700 would save the program to page 2 on the ce nd autorun, When the program - reloaded, it will come ug in the same meds (SLOG/FAGT) as when it was saved. To save the program on, say, page 6 instead of page 2, line 7708 would read "RAND USR 12724".

o 20K af data, Thus it is extremely unlikely,

SIMC-LINK WOL.4 NO-1 JAH FEB 86

Having saved a program, it aust be entered in the directory,

q Sa 30, entering RAND USR 13303 brings up the SADIS menu. Pressing E gets a pr a asking which page you want to name, followed by entry of the prograa nane, Having done this, you must

re-save the updated directory to page i. This is offered as a Y/N option when you finish making directory entries, or it can be done by pressing 3 at the main menu. Now, if you hit L at the asnu, the directory appears, listing pages l thru 20 and

their contents. Any program may de loaded by entering its page nuaber, or you may copy the directory to your printer.

D, for DISK UTILITIES, provides selection of PROGRAM or DATA mode, of Disk Drive 4,8,£, or Dj Single or Double Density, and also a Clear Directory command. In Data node, all

Variables are saved y loaded, without the BASIC program. When re-loading data, na test is made tor variables space. Variables aust already have been dimensioned or declared 50 there is enough room between VARS & E LINE for the disk file to load into. With an understanding of these limitations, the Bata mode can be very useful, ]'ve successfully programmed a version of HOII.5 which saves & loads data files ONLY} up te 20 14,000 byte text files, each saved with a filename string. The progran will sequentially search a disk for any named file, and print an automatically maintained directory. Ta sure that versions af 1X PRO-FILE ior other file handling programe) could be modified to sequentially search a whole disk, if necessary, to find an entry.

CPs and BUS LOADING: I had just gotten a few programs saved to disk, and was marveling at the speed of program access, when I realized [ had problems- random load errors galore, Bytes were simply dropping gut of programs. Susfecting bus speed/loading problems, I singled aut 2 possible culprits: ay CFU, and the ribbon cable provided hy Aerco. The NEC D7a0¢ CPU in my computer is a notoriously substandard 2180 chip, so 1 replaced it with a naw Zilog 1908, The 130B is designed for ogeratian at up to GMHz., thus has lower intrinsic capacitance, and "stiffer" bus drivers than the siower versions. At the sane time, I mixed the ribbon cable, and plugged everything into ay new JLO d-slot aotherboard. A ribbon cable can have 3-ió tiaes the capacitive crosstalk as a sotherboard the same length, so I figured this would help. Nat

so simple, though, The sale edge connector on the FD-2X is a airror-image of that needed by the JLE motherboard! Thus, 1 had to fashion a "side-swapper* adapter to plug sere ita together. Having done all this, the problems completely disappeared, and the disk system has been 100% reliable aver since. 1 don’t know whether the CPU or the aotheroaard was the significant factor, but the combination licked the problem.

IN CONCLUSION, the AERCD FD-23 system has made a “disk convert" out of this 2481 hobbyist. The hardware is of good quality and is well asseabled. The O08 controi program is certainly utilitarian, although saae resourceful programming can make it do some impressive things. The existing 003 control software simply doesn’t take advantage of the FB-11 hardware’s potential. ferco’s documentation is quite therough, and provides a few clues to accessing nore sophisticated 08

commands thru machine code. The incredible speed of reliabie access to a large number of prograas or files makes it easy to averlook the pedo the DOS.

PAGE 3.

HOW TO MAKE BACK-UP COPIES OF SPECTRUM COPY-PROTECTED PROGRAMS

A A AA]

Karia Rahesat

Special thanks to Arial Frailich for advise and for technical

information.

IR ZA IE RIAD DAI

NOTES THIS ARTICLE 15 PROVIDED FOR USE WITH YOUR PERSONAL LIBRARY ONLY AND MOT FOR STEALING COPYRIGHTED SOFTWARE.

How sany tines have you tried to wake a back-up copy of your now software? IE seems that whenever you try the copy you have, it doesn't work. Some of these programs may kave anti-werge, headerless files, jerky leaders, short leaders, files too close together, fast loaders, false headers] some may be 48k long or have yet other types of copy protection.

Let's discuss some of these copy protection devices. First we have the anti-MERSE program, which prevents the BASIC loader iroa being MERGEd; it can only be LOADed. This can he bypassed with tast reflexes and knowing when to hit the BREAK key. Start by using the header reader program to find the autostart line number of the program. Start LOADiag the program and press the BREAK key when the LOAD is just about to finish. (Experiment here.) You should see an error report stating that BREAK was pressed in some line nuaber. Save the program with the original autostart line number.

The next step is to determine whether the next program is headerless, machine code or BASIC. If it’s less than 48k loag - say 38-40k - LOAD the code at a higher address than normal. This prevents the program from autorunning, If the file doesa’t start with a header, then a special LOAD routine is used for LOADiag the headerless tile, This code may be located anywhere in nesory and the most likely place is in a DATA statement for POKEing or in the variables area. Use the header reader on the BASIC program and find the autostart number. LOAD .the program as described above for anti-MERGE programs. Now SAVE the file without any autostart line. LOAD HOT-Z and PRINT PEEK 23427+2544PEEK 23628. This will tell you where the variables area starts, Use HOT-2 again at the address you have found above.

You should non see three LD's, a SC and a call to 0534H, It you have found it, Congratulations! You have just found = a routine for LOABing the headerless file. Here?s how it works: tirst the IX register is LOADed with the start address af the tile. The DE register is LOADed with the number of bytes, then the A register is LGADed with FFH or QOH - FFH to load the Data portion or 00H to load the Header portion. A CALL is sade to the home ROM routine which does the actual loading. Finally, the routine jumps to the the program which has just been loaded.

EXAMPLE: LD IX,8000H -~ START ADDRESS OF FILE 1D DE,1200H - NUMBER OF BYTES TO LOAD {Program length) LD A,FFH - LOAD HEADER ONLY SUF - SET CARRY FLAG CALL 0554H -~ GOTO LD_BYTES ROUTINE IN ROM IP 30324 - RUN PROGRAM

LOAD rotines for headerless files usually consist of only 7 bytes. This also applies to false headers. Fast LOADers are the trickiest of all protection devices. They are vary fussy

Dano b

about clean heads and azimuth alignment. Fast LOADers camnot be fast LOADed themselves} they require a normal {1500 baud) BASIC and machine code program to be loaded first. Every fast LOADer I have hides its fast LOAD code ia the Variables area. This can only be discovered with a header roador. The header reader will let you know if any Variables area has been taken. If so, the code is in that areaj if not, the code is in either a REM or DATA statement. To tind out where the code starts in the Variables area, use PRINT PEEK 23627+2543PEEK23628, Thea use HOT-2 to disasseuble from the address you found with the PEEK, The code varies trom progras to program. You'll just have to experiment. Incidentally, all the above is true for short leaders, jerky loaders and 48k long headeriess files. Jerky leaders or pulsed leaders are the aost troublesome type of copy Protection} copying can only be done via tape to tape. This protection device is now in widespread use. If your program uses jerky or pulsed leaders, you will ses the bars (while LOABing the program) go up and down and a short, almost inau dible bleep will go off between bars. As mentioned above, use tape-to-tape copy for back-up. Trying to rid the BASIC of colour control characters issome times difficult: the text bytes themselves aay have beenalte redj the RASP system variable may have baen POXEd with 255; and other POKES say exist, This complicates things a Jot. Your best bet is to use HOT-Z to disassemble the BASIC program proper and experiment,

In 1984, a new copy protection device was introduced, It has not been extensively used by software houses yet. It goes by the name of TONING and is accomplished by altering the LOAD head er patterns, This too requires special code tor ¡0Abias ihe prog ran into the computer and, likewise, the loader part is LOADed normally. There are three types of tone leaders: wide, Short and narrow, The "wide" leader produces bars which are further apart than normal bars. The "short" leader shortens the ‘silent gan" between programs - this "silent gap’ is created and expected by the computer and aust therefore be present, This *short* leader is of course not LOADable normally. The "tone" leader uses narrower bars than normal, Use tape-to-tape copy tor backing up Toned programs.

Let's now discuss Tape Copiers. We're not taiking about the tape copiers which copy programs from one tape to another via the computer le.3., Cameron Hayne's Tape2Tape). These new ones will LOAD the program into the computer añd the SAVE it ising the ordinary SAVE routines, giving you clean LOADs. Note that these programs are intended for back-up copies only, aot for pirating! Some of these programs are called Kklone 1.0 and l.l, Pirate?b, IJpclone, 007spy, Naxspy, Tricky, Tape copier 7, Tape copierá. The tape copier will LOAD the file either headerless or with the header and SAVE it in its orginal fore. Special copiers will LOAD a full 49k program either headerless or with header or a tile larger than 10k long. Some will evea copy a 61k long file and still work without errors. Whea backing up a program with a tape copier, don’t expect too much. These programs can obviously only handle certaia situations} again, the only way to find out is to experiment. Your best bet is to try several programs and use your machine code know-how, Software houses are of course continually delevopiag new techniques in software protection. Some programs réquire you to purchase a piace of hardware along with the program. The

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the same hardware to rus). And... if the program doesn't detect the hardware, the program NEWs itself.

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A METHOD TO PROTECT MORE THAN ONE LINE FROM DELETION (ZX81)

First, before entering anything else, line or lines to be protected,

enter the

Next enter POKE 16509,40 (Actually you could POKE any number betwaen 40 and 63). This should change the number of the first line to a letter followed by 3 digits.

Then enter the rest of your program

The lines present when you POKE'ed 16509 will then be visible at the end of the program but cannot be changed or deleted in the normal way, and now there is no easy way of finding out which address has to be POKE'ed to change the line number back to a "proper" one, as entering the main body

of your program will have moved the POKE'ed byte up in memory,

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